Electrical equipment is typically protected from overloads or over-voltages by fuses or circuit breakers which disconnect the equipment from a power source when an overload or overvoltage condition occurs. Fuses are often preferred for this purpose because of their low cost. Fuses, however, suffer from the disadvantage of requiring replacement. Hence, fuses are typically contained in a holder designed to facilitate easy replacement. The holder typically includes a holder or base portion electrically connected in series between the power source and the equipment being protected. The fuse is placed in the holder and a cap is attached by suitable screw threads or a bayonet engagement to hold the fuse in the holder and to complete the electrical circuit.
Circuit breakers have the advantage of not requiring replacement. Typical circuit breakers can be either self-resetting or manually resetable. With either type the circuit breaker is ordinarily soldered in place because replacement is normally not required in typical use.
An example of electrical equipment which makes extensive use of fuses or circuit breakers is the various amplifier stations in a community antenna television (CATV) signal distribution system. A typical amplifier station is shown in Lieberman et al. U.S. Pat. No. 3,717,813 wherein various input/output lines and the power supply are fused. CATV systems are subject to various overload conditions such as power line surges, short circuits, lightening induced surges, and the like. Such overload conditions can burn out a substantial number of fuses particularly where the surge travels from one amplifier station to other amplifier stations. Replacement of a large number of fuses is time consuming and expensive because the particular amplifier stations with burned out fuses must be located and individually accessed.
The use of circuit breakers in such systems is highly advantageous because replacement is not ordinarily required. Self-resetting or cycling circuit breakers provide a further advantage where the overload condition is due to a momentary power or voltage surge or short circuit. Many users desire fuses, however, because of their low cost and many CATV systems have equipment presently using fuses.
To provide flexibility for manufacturers, it is desirable to provide equipment which can accommodate either fuses or circuit breakers as the customer desires. Furthermore, owners of existing equipment often desire retrofitting their existing equipment with circuit breakers. In order to expeditiously accommodate such options, it is known in the prior art to modify fuse holder caps to accommodate circuit breakers. One such known modification includes drilling a hole through the top of the fuse holder cap to allow the longer circuit breaker to extend through the cap, bonding the cap to a circuit breaker envelope, soldering the circuit breaker lead to the fuse holder cap, and providing a spacer between the base of the fuse holder and the circuit breaker. All of this modification requires substantial effort resulting in costly and time consuming construction. Furthermore, the complexity of manufacture results in substantial scrap and the assemblage, of miscellaneous parts results in low reliability.